Impacts of Orthophosphate Addition on Chloramine Decay and Biofilm Development in a Model Drinking Water Distribution System

IF 11.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Water Research Pub Date : 2025-04-25 DOI:10.1016/j.watres.2025.123712

Mahmoud H. Badawy, Mitchell G. Cooke, Kimia Aghasadeghi, Sigrid Peldszus, Robin M. Slawson, Peter M. Huck

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Abstract

Orthophosphate is commonly added as a corrosion inhibitor in drinking water distribution systems (DWDSs). However, there is limited understanding of the interrelationships between its addition, monochloramine decay, and biofilm growth. Further research is needed to evaluate its potential to accelerate monochloramine decay and promote biofilm development. This study examines the impact of orthophosphate doses (0 to 4 mg PO₄^3-/L) on monochloramine decay and biofilm growth using model distribution systems (MDSs) at a 10-day residence time, fed with phosphorus-limited water. Findings showed that, in addition to expected enhanced microbial growth, biofilm formation potential, and metabolic activity (i.e., carbon utilization), orthophosphate addition also increased monochloramine decay. For instance, biofilm growth increased from 2.9–3.2 to 5.3–6.3 log CFU/cm² between 1 and 4 mg PO₄^3-/L, with the most substantial increase observed between 1 and 2 mg PO₄^3-/L (an increase of more than 2 log units). Around day 52, changes in metabolic activity, biofilm formation potential, and biofilm growth in MDSs with added orthophosphate suggested a shift in the microbial community from early colonizers to bacteria thriving in biofilms. A correlation between biofilm profiles and monochloramine decay was apparent, with significant positive correlations between total chlorine decay and (i) biofilm HPC (R² = 0.86, p < 0.001), (ii) biofilm formation potential (R² = 0.73, p < 0.01), and (iii) metabolic activity (R² = 0.81, p < 0.001). Higher orthophosphate concentrations (2-4 mg PO₄^3-/L) were linked to greater biofilm growth and monochloramine demand, while 1 mg PO₄^3-/L had minimal impact. Total chlorine decay coefficients ranged from 0.0033 h^-1 (control) to 0.0072 h^-1 (4 PO₄^3-/L) in the phase of further biofilm development. These findings emphasize that orthophosphate usage in DWDSs needs to balance corrosion control aspects with effects on water quality (e.g., biofilm growth and monochloramine stability).

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正磷酸盐添加对饮用水配水系统氯胺降解和生物膜发育的影响

正磷酸盐通常作为缓蚀剂添加到饮用水分配系统（dwds）中。然而，对其添加、单氯胺衰变和生物膜生长之间的相互关系了解有限。进一步的研究需要评估其加速单氯胺衰变和促进生物膜发育的潜力。本研究通过模型分配系统（mds）研究了正磷酸盐剂量（0至4 mg PO43-/L）对单氯胺衰变和生物膜生长的影响，并在10天的停留时间内饲喂限磷水。研究结果表明，除了预期的微生物生长、生物膜形成潜力和代谢活性（即碳利用）的增强外，正磷酸盐的添加也增加了单氯胺的衰变。例如，在1 ~ 4 mg PO43-/L之间，生物膜生长从2.9 ~ 3.2 log CFU/cm2增加到5.3 ~ 6.3 log CFU/cm2，其中在1 ~ 2 mg PO43-/L之间的增幅最大（增幅超过2 log单位）。在第52天左右，添加正磷酸盐的mds中代谢活性、生物膜形成潜力和生物膜生长的变化表明微生物群落从早期定植到生物膜中繁荣的细菌的转变。生物膜形态与单氯胺衰变之间存在明显的相关性，总氯衰变与(i)生物膜HPC之间存在显著正相关(R2 = 0.86,p <；0.001), （ii）生物膜形成电位(R2 = 0.73,p <；（iii）代谢活性(R2 = 0.81,p <；0.001)。较高的正磷酸盐浓度（2-4 mg PO43-/L）与更大的生物膜生长和单氯胺需求有关，而1 mg PO43-/L的影响最小。在生物膜进一步发育阶段，总氯衰变系数为0.0033 h-1（对照）~ 0.0072 h-1 （4 PO43-/L）。这些发现强调，在dwds中使用正磷酸盐需要平衡腐蚀控制方面和对水质的影响（例如，生物膜生长和单氯胺稳定性）。

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.